AskUserRowSummary = Literal['User answered', 'Question failed']The summaries an ask_user row may collapse to.
Narrows ToolCallMessage.defer_success so the transcript cannot be passed where
a summary belongs — the constraint that keeps user-typed answers out of
tool.result hook payloads.
Of the four *_SUMMARY constants below, only ASK_USER_ANSWERED_SUMMARY and
ASK_USER_FAILED_SUMMARY are members: the other two are hook bodies that no row
ever renders. Literal[...] cannot reference a plain string constant, so those
two values are restated here; both are annotated with this alias, so ty rejects
a reword that drifts. test_row_summary_alias_matches_its_constants pins it too.